Bromeliad-living spiders improve host plant nutrition and growth

Although bromeliads are believed to obtain nutrients from debris deposited by animals in their rosettes, there is little evidence to support this assumption. Using stable isotope methods, we found that the Neotropical jumping spider Psecas chapoda (Salticidae), which lives strictly associated with the terrestrial bromeliad Bromelia balansae, contributed 18% of the total nitrogen of its host plant in a greenhouse experiment. In a one-year field experiment, plants with spiders produced leaves 15% longer than plants from which the spiders were excluded. This is the first study to show nutrient provisioning in a spider-plant system. Because several animal species live strictly associated with bromeliad rosettes, this type of facultative mutualism involving the Bromeliaceac may be more common than previously thought.

Early development and nutrition of cover crop species as affected by soil compaction

A good cover crop should have a vigorous early development and a high potential for nutrient uptake that can be made available to the next crop. In tropical areas with relatively dry winters drought tolerance is also very important. An experiment was conducted to evaluate the early development and nutrition of six species used as cover crops as affected by sub-superficial compaction of the soil. The plants (oats, pigeon pea, pearl millet, black mucuna, grain sorghum, and blue lupin) were grown in pots filled with soil subjected to different subsurface compaction levels (bulk densities of 1.12, 1.16, and 1.60 mg m(-3)) for 39 days. The pots had an internal diameter of 10 cm and were 33.5 cm deep. Grasses were more sensitive to soil compaction than leguminous plants during the initial development. Irrespective of compaction rates, pearl millet and grain sorghum were more efficient in recycling nutrients. These two species proved to be more appropriate as cover crops in tropical regions with dry winters, especially if planted shortly before spring.

Root growth and cotton nutrition as affected by liming and soil compaction

Soil columns were produced by filling PVC tubes with a Dark Red Latosol (Acrortox, 22% of clay). A compacted layer was established at the depth of 15 cm in the columns. In the compacted layer, soil was packed to 1.13, 1.32, 1.48, and 1.82 Mg kg(-1), resulting in cone resistances of 0.18, 0.43, 1.20, and 2.50 MPa. Cotton was cropped for 30 days. Lime was applied to raise base saturation to 40, 52, and 67%. The highest base saturation caused a decrease in phosphorus (P) and zinc (Zn) concentrations in the plants. A decrease in root dry matter, length and surface area was also observed. This could be a consequence of lime induced Zn deficiency. Root growth was decreased in the compacted layer, and complete inhibition was noticed at 2.50 MPa. Once the roots got through the compacted layer, there was a growth recovery in the bottom layer of the pots. The increase in base saturation up 52% was effective in preventing a decrease in cotton root length at soil resistances to 1.20 MPa. Where the roots were shorter, there was an increase in nutrient uptake per unit of root surface area, which kept the plants well nourished, except for P.

Kinetics of zinc uptake and anatomy of roots and leaves of coffee trees as affected by zinc nutrition

Zinc (Zn) uptake kinetics and root and leaf anatomy were studied in coffee trees grown in nutrient solutions with or without Zn. Leaves and roots were sampled and cuts were made in the medium part of the leaves and in root tips and observed under an optical microscope. Plants grown without Zn showed an increase in root and in root stele diameter. There was also an increase in epidermis thickness and in the cross-sectional area of the cortex and stele due to Zn deficiency, but the diameter of xylem vessels was decreased. An increase in root cortex and stele diameter provided for an increased surface for nutrient uptake. Accordingly, C(min) was decreased from 13.8 to 3.4 mu mol L(-1) and V(max) increased from 0.50 to 2.1 mu mol cm(-2) h(-1) .

Influence of nutrition on the glucose absorption and tolerance test in horses submitted to different fasting periods

Four groups of horses of Brasileiro de Hipismo bred were submitted to fasting for 24 and 48 hours in order to study the absorption capacity of the small intestine. Two groups were fed with coast cross grass (Cynodon dactylon) and the other two groups with coast cross pasture and grains. At the end of the fasting periods, the groups received 1g of glucose/kg of body weight in a 20% solution through a nasogastric tube. Blood samples were collected immediately before and 70, 60, 120, 180, 240, 300, and 360 minutes after glucose administration. Glycemia was determined by the orthotoluidine method and insulin by radioimmunoassay. The animals which received grains showed larger increase in glycemia and insulinemia than those maintained on pasture regimen alone. The 48-hour fasting period induced higher glycemia and insulinemia levels than those observed after 24-hour fasting.

Long-term nutrition education reduces several risk factors for type 2 diabetes mellitus in Brazilians with impaired glucose tolerance

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Enzyme production by solid-state fermentation: Application to animal nutrition

Many microorganisms that decompose lignocellulosic material are being studied as producers of enzymes to perform enzymatic hydrolysis of the lignocellulosic material present in residues from the agroindustries. Although the cellulose and hemicellulose present in these materials have their value for feeding cattle, their bioavailability requires breakdown of the bonds with indigestible lignin. Predigestion of such materials with ligninases, xylanases and pectinases (cellulase free) may transform the lignocellulosic substrate into a feed with greater digestibility and higher quality for ruminants.. This review provides an overview of variables to be considered in the utilization of fungal plantdepolymerizing enzymes produced by solid-state fermentation from agricultural production residues in Brazil. (c) 2007 Elsevier B. V. All rights reserved.

Serum Vitamins in Adult Patients With Short Bowel Syndrome Receiving Intermittent Parenteral Nutrition

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Broiler breeder trace mineral nutrition and feeding practices on embryo progeny development

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Fungus incidence on peanut grains as affected by drying method and Ca nutrition

An experiment was conducted to study the effects of liming and drying method on Ca nutrition, fungus infection and aflatoxin production potential on peanut (Arachis hypogea) grains. Peanut cv. Botutatu was grown in the absence or presence of liming to raise the base saturation of the soil from 20 to 56%. Calcium contents of the soil were increased from 5.5 to 14.6 mmol((c))kg-1 and pH from 4.2 to 4.9. After harvest, plants and pods were dried in (1) shade, (2) field down to 100 g water kg-1 (3) field down to 250 g water kg-1 and transferred to a forced-air oven at 30°C, (4) field down to 360 g water kg-1 and transferred to a forced-air oven at 30°C. Calcium contents were analyzed in the grains, pericarps and seed coats. The incidence of Aspergillus spp., Penicillium spp., Rhizopus spp. and potential aflatoxin production in vitro were evaluated, as well as the seed coat thickness. The seed coat was thicker when peanut was grown in the presence of lime, leading to a decrease in seed infection by Aspergillus spp. and Penicillium spp. When plants were dried in shade, the growth of aflatoxinogenic fungi was independent of liming. However, in plants dried in the field or field + oven, the development of these fungi was decreased and even suppressed when the Ca content of the seed coat was increased from 2.2 to 5.5 g kg-1.